I am trying to make Au coating (by thermal evaporation) on borate glass surface for some conductivity experiments. I observed that the adhesion between the glass surface and the coating is not good and can be removed easily. I tried to mildly etch the surface layer by HNO3 and then used ethanol for ultrasound cleaning. The sample was dried in an oven at 80 degree centigrade prior to the coating.
You can try Chromimum coating very few nanometers prior to gold deposition to enhance adhesion
I agree to Mr Tombak, Chrominium will help alot 5-10 nm are enough. If that is not available, Titanium works just as good. In addition, you can try an oxygenplasma prior to coating, to remove stuff from the surface
Oxygen plasma etch, then deposition of < 10nm of Cr or Ti, then immediate deposition of Au. Breaking vacuum between any of the processes will decrease the adhesion. How thick of a layer are you depositing? Can you add substrate rotation? Are you orienting the substrate perpendicular to the source? All of these things will have an impact on the resulting film.
There are many materials that can be used as a binder layer, depending on the impact on your experiment. I've used Cr, Cu, Ti, and some dielectrics (TiO2 should adhere pretty well, and I have also used Al2O3). Just a very brief deposition will work - I have used a "few Angstroms" (per the QCM, not characterized on the sample) to adhere a silica overcoat layer to Au for a first-surface mirror. It does not even need to be a continuous layer, just sufficient adhesion overall to adhere the structure together.
Magnetron Sputtering and the addition of an adhesion layer after oxygen plasma/UV ozone treatment to increase surface energy.
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